Improvement of the wear and corrosion resistance of oil pump materials using plasma immersion ion implantation

A typical oil pump used in oil wells consists of a piston column, piston sleeve and ball valve. The working environment in an oil field is harsh and unforgiving, and the piston column in the oil pump is very vulnerable to wear and corrosion. Hence, improving the wear and corrosion resistance of the piston which is made of 45^# steel is critical to the efficiency and profitability of oil companies. Even though ion implantation is an effective means to enhance the surface properties of the materials, the irregular shape and large dimension of the column make conventional beamline ion implantation very difficult. As the technique of plasma immersion ion implantation circumvents this line-of-sight restriction, it is a suitable technique to improve the wear and corrosion resistance of the components in an oil pump. A treatment process involving RF plasma nitriding and ion beam enhanced deposition (IBED) has been developed. The microhardness, mass loss due to wear, and coefficient of friction of the untreated and treated samples were measured. A salt fog test was also conducted to evaluate the resistance against rusting. The results indicate that the treatment improves the wear and corrosion resistance of the 45^# steel samples significantly, and that the combined RF plasma nitriding and IBED process is more effective than a single RF plasma nitriding step. © 1998 Elsevier Science S.A.